| Message ID | 1455698012-814399-1-git-send-email-arnd@arndb.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02/17/2016 02:32 AM, Arnd Bergmann wrote: > The "translate_scan" function in rtl8712 uses a lot of stack, and > gets inlined into its single caller, r8711_wx_get_scan, which > in some configurations now blows the 1024 byte stack warning > limit: > > drivers/staging/rtl8712/rtl871x_ioctl_linux.c: In function 'r8711_wx_get_scan': > drivers/staging/rtl8712/rtl871x_ioctl_linux.c:1227:1: error: the frame size of 1032 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] > > This somewhat reduces the stack usage by moving the translate_scan > function out of line with the noinline_for_stack annotation. > It might be possible to modify translate_scan() a little further > to reduce the stack usage, but with this patch, we can build without > the warning, the the call chain to get here is rather predictable > (sys_ioctl->vfs_ioctl->sock_ioctl->dev_ioctl->wext_ioctl-> > r8711_wx_get_scan). > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/staging/rtl8712/rtl871x_ioctl_linux.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) As there is no reason for translate_scan() to be inlined, this patch seems reasonable The largest user of stack likely comes from the line "struct iw_event iwe". Changing that to a pointer, and using kalloc to acquire the space would likely clear the compile message, but that would require many more changes. Acked-by: Larry Finger <Larry.Finger@lwfinger.net> Larry > > diff --git a/drivers/staging/rtl8712/rtl871x_ioctl_linux.c b/drivers/staging/rtl8712/rtl871x_ioctl_linux.c > index db2e31bcdd77..a15f3ce70223 100644 > --- a/drivers/staging/rtl8712/rtl871x_ioctl_linux.c > +++ b/drivers/staging/rtl8712/rtl871x_ioctl_linux.c > @@ -137,7 +137,7 @@ static inline void handle_group_key(struct ieee_param *param, > } > } > > -static inline char *translate_scan(struct _adapter *padapter, > +static noinline_for_stack char *translate_scan(struct _adapter *padapter, > struct iw_request_info *info, > struct wlan_network *pnetwork, > char *start, char *stop) >
On Wednesday 17 February 2016 20:20:15 Larry Finger wrote: > > --- > > drivers/staging/rtl8712/rtl871x_ioctl_linux.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > As there is no reason for translate_scan() to be inlined, this patch seems > reasonable The largest user of stack likely comes from the line "struct iw_event > iwe". Changing that to a pointer, and using kalloc to acquire the space would > likely clear the compile message, but that would require many more changes. > > Acked-by: Larry Finger <Larry.Finger@lwfinger.net> > > Thanks! I believe that the problem is the combination of "struct iw_event" and the two buffers "u8 wpa_ie[255], rsn_ie[255];" and "u8 wps_ie[512];". Just to document this better: if we ever decide to use a dynamic allocation, I would allocate all of the above together. Arnd
Of course, we still reach almost the same maximum stack usage as before because we're going to put the function on stack in the end anyway. regards, dan carpenter
diff --git a/drivers/staging/rtl8712/rtl871x_ioctl_linux.c b/drivers/staging/rtl8712/rtl871x_ioctl_linux.c index db2e31bcdd77..a15f3ce70223 100644 --- a/drivers/staging/rtl8712/rtl871x_ioctl_linux.c +++ b/drivers/staging/rtl8712/rtl871x_ioctl_linux.c @@ -137,7 +137,7 @@ static inline void handle_group_key(struct ieee_param *param, } } -static inline char *translate_scan(struct _adapter *padapter, +static noinline_for_stack char *translate_scan(struct _adapter *padapter, struct iw_request_info *info, struct wlan_network *pnetwork, char *start, char *stop)
The "translate_scan" function in rtl8712 uses a lot of stack, and gets inlined into its single caller, r8711_wx_get_scan, which in some configurations now blows the 1024 byte stack warning limit: drivers/staging/rtl8712/rtl871x_ioctl_linux.c: In function 'r8711_wx_get_scan': drivers/staging/rtl8712/rtl871x_ioctl_linux.c:1227:1: error: the frame size of 1032 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] This somewhat reduces the stack usage by moving the translate_scan function out of line with the noinline_for_stack annotation. It might be possible to modify translate_scan() a little further to reduce the stack usage, but with this patch, we can build without the warning, the the call chain to get here is rather predictable (sys_ioctl->vfs_ioctl->sock_ioctl->dev_ioctl->wext_ioctl-> r8711_wx_get_scan). Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/staging/rtl8712/rtl871x_ioctl_linux.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)